The issue is not damage protection for needing the RCD as such, but if using a spade or similar to cut in to the cable could you touch the core without being in contact with the CPC and so tripping the protection?Good question, but as I have no idea how deep its been buried and also its only protected by a copper sheath which is not going to be anywhere near as strong as SWA (I would guess).
So anything with an adequately rated earthed shield (to clear OCPD) is safe. It might not be suitable for direct burial as not strong enough, but that is a problem that is independent of RCD protection or not!